A FRAGMENT ON CAUSE AND EFFECT.

“Thought is a secretion of the brain” was the announcement of a distinguished naturalist and physiologist, which excited strong aversion to those studies and views of nature which could thus degrade, as it appeared to do, the dignity of so important a function of life. What was, probably, meant, however, by the saying, is the physiological truth that the brain is the organ of thought in a manner analogous to that in which a gland is the organ of secretions, or a muscle of contractions, or the heart and vascular system of circulations. Thought no more resembles a secretion, however, than this resembles a contraction, or than either of these resembles the movements and effects of circulation; not so much, indeed, as these three resemble each other; yet, like all these three kinds of action, it is dependent, as physiological investigations show, on the intimate structure and vital activity of a special tissue, and its living arrangements and special changes in the brain. It is altogether likely that this is what was meant, and all that was meant, by the somewhat sinister and disagreeable observation that “thought is a secretion of the brain.,, Men of science sometimes resort to paradoxes, figures of speech, concrete ways of stating truths in science, which those who are ignorant of the science and its real ground of evidence, but imagine that they can judge of its conclusions, are almost sure to misunderstand. Irony is not a more dangerous figure than such a use of comparisons and illustrative figures of speech. Men of science are supposed, except by other men of science, to be literal and exact, and unlike poets, in all their utterances, and when, as Professor Carl Vogt did in the present instance, they seek to impress the imagination by a comparison or figure which is made at the expense

of sentiment, their expositions are almost sure to be misconceived, not only by those who are ignorant of their science and its grounds of inference, but even by the more sentimental and unreflective student of the science. What these persons seem to have supposed to be meant is not that thought and its expression are allotted to the brain as a secretion is to a gland, but that thought is a function in life which, as function, is of no more worth or dignity than the functions of the kidneys or of a cutaneous gland. It is altogether probable, however, that a certain feeling of impatience or contempt for the sentimental shallowness which could so misinterpret a scientific comparison, and confound it with moral or practical considerations is a real motive prompting to the utterance of shocking paradoxes, in disregard alike of the practical effect and of scientific clearness and discrimination in the communications of truth. Native common sense is too apt to be coarse and barbarous in its manners, and too inconsiderate of weakness.

We will not venture to say that this was the case with the distinguished biologist whose words have been the cause of so much scandal. The metaphysical doctrine of materialism so often charged against or imputed to such scientific thinkers, is, in fact, a doctrine quite foreign to science, quite out of its range. It belongs, so far as it is intelligible, to the sphere of sentiment, moral feeling and practical principles. A thinker is properly called a materialist when he concludes that his appetites and passions and actions, having material objects and results for their motives, are those most worthy of serious consideration. This does not imply that he believes that natures so different as thoughts, sensations, bodies liquid and solid and their movements, are all fundamentally of the same nature, or are natures some of which are derived from certain other more fundamental ones among them: the spiritual from the material ones. It does not imply the opinion that thought is constituted of motions or liquids, does not even imply that the materialist thinker believes in, or knows anything about, the truth that actual thinking depends, phenomenally, on the tissues, structures and conditions of an organ, as intimately as the liquid secretions and the internal and external movements of a living body do.

Scientific doctrines and investigations are exclusively concerned with connections in phenomena which are susceptible of demonstration by inductive observation, and independent of diversities or resemblances in their hidden natures, or of any question about their metaphysical derivation, or dependence.

That like produces like, and that an effect must resemble its cause are shallow scholastic conceptions, hasty blunders of generalization, which science repudiates: and with them it repudiates the scholastic classification or distinction of material and spiritual which depended on these conceptions, or supposed that a cause conferred its nature on its effect, or that the conditions of a cause by the combination of their natures constituted the nature of the effect. This, in a sense,—in an identical or tautological sense—is indeed true; but from this true, though identical, sense a false and mischievous one was generalized, and still continues to corrupt and misinterpret the results of scientific observation.

In discovering anything to be the cause of something else we have added to our knowledge of the nature of the first thing. We have included in our conception of this thing the attribute of its producing, or being the cause of, the second. If now this attribute of it be the most prominent quality of it in our regard, as it is in contemplating a cause qua cause, the effect may, in an identical sense, be said to be constituted by its cause. In this view all the other attributes of the cause are subordinated to the attribute of producing a defined effect, or are regarded as accidental or non-essential attributes, and this is the view of the elementary relations in geometry and mathematics generally which abstraction produces, and is the source of the semblance of demonstrative certainty, and objective necessity which mathematical theorems have. But when science discovers, by induction or empirically, a new cause, the thing previously known by other attributes, to which is now added the attribute of producing a given or defined effect, has nothing in its essential or previously defining attributes at all resembling, implying or constituting its effect, and its newly discovered attribute of producing this effect remains among the added, subordinate or accidental attributes of such a cause. In its essence it does not

imply, suggest or resemble its effect, and in this case the assertion that the nature of the cause determines or defines the nature of its effect, is clearly seen, so far as it is true, to be an identical proposition, meaning only that the production of the defined effect is a part, and a subordinate part, of the nature of a thing. The definition of the effect is added to that of the thing which is its cause, at least while we are contemplating this as the cause of the defined effect, and it is only by refunding to the effect what we have thus borrowed from it that we arrive at the metaphysician’s mathematical conception of causation, the transference of the nature of one thing, that is, the cause, to another thing, its effect. In mathematics the elements of demonstration are so selected, by abstraction, and their definition so determined that this transference of nature is what is ostensibly done; though it is no more really done than in inferring consequents from antecedents, or effects from causes in so-called empirical science. In all cases where this appears to be the character of the connection of antecedent and consequent, or cause and effect, the transference of the nature of the cause to its effect, is only a restoration to the effect of natures borrowed from it, or into which it is resolvable by analysis. This fact is observed especially in mathematical inference, since such inference is always from a complex antecedent, or from the combination of a number of conditions, of which the aggregate is not known, named or defined by any attributes other than those which by the analysis and recombinations of mathematical demonstrations are shown to depend on the most obvious and elementary truths of our experience of measured quantities. The protasis of a geometrical theorem by the aid of geometrical constructions previously shown, or, when ultimate, simply assumed to be legitimate, is resolved into conditions which, recombined, are the apodosis or conclusion of the proposition. These conditions may be used to define the natures of both the antecedent or reason, and the consequent, and by this means their natures become identical. And both are analyzed ultimately in the course of a series of demonstrations into a few axioms, and these axiomatic truths implied in a few definitions. But not only in the mathematical, but also in the so-called empirical discovery of the connections of antecedent and consequent, or cause and effect, the antecedent or cause is almost always a combination of conditions, or a concurrence of things, relations and events, the definition of which in their aggregate, in merely logical consideration, may as well be the effect which follows, provided this is sufficient for defining it, as be anything else; since this aggregate of conditions is not usually denoted by a single name, the connotation of which would define its nature. Yet for practical and scientific purposes this aggregate is best defined by the enumeration of the conditions that compose it, to which observation adds the fact, or nature, that it will whenever it exists be followed by a given or defined effect. In this case the conditions which constitute the cause do not constitute the effect. They are simply followed by the effect, whose nature is wholly unlike that of its cause, or is like and is implied in its cause only so far as the capacity of producing it may be thought of identically as a part of the nature of its cause. Thus a stone, or any body denser (1) than the air, left unsupported (2) above (3) the surface of the earth, will fall (4) to it, is a proposition in so-called empirical science, in which the conditions (1) (2) (3) form an aggregate to which if we add as a part of its nature the result (4), that is, add the unconditional tendency to fall inferred from facts of observation, then the fall is a necessary consequence of the nature of its antecedent conditions, and it is like or is implied in this nature, quite as truly as any mathematical consequence is necessary, or is implied in mathematical protases of causes or antecedents. But ordinarily physical philosophers are not so anxious to make a scholastic show of demonstration as to surreptitiously add (4) to the group of conditions (1) (2) and (3) so as to make out their proof on the maxims that like produces like, or that effects resemble or partake of the nature of their causes. These maxims are really no more true of abstract reasonings in the elementary demonstrations of geometry; but the aim of these elementary reasonings justifies the procedures which give apparent countenance to their maxims.

Other and real illustrations vaguely related to these apparent ones are given in the organic world, in the phenomena of assimilation

and reproduction. Tissues turn nutriment into substances of the same kind as their own. Offspring resemble their parents. These facts, together with the geometrical principle of Sufficient Reason appeared to be sufficient grounds with scholastic philosophers for generalizing the identity of natures in real causes and effects. But, in fact, the very opposite is true. Elementary relations of antecedence and consequence are always those of unlikeness. A simple nature or phenomenon A is invariably followed by, or joined with, another different one B. Weight in a body manifested to us primarily by pressure, or in the tension of our muscles through the statical muscular sense, is a simple nature not resembling or implying at all the downward movement which always follows it when isolated or freed from other forces or conditions that are of a nature to produce an opposite effect, namely, an elastic movement, or bearing upward, and are as unlike this effect as weight is unlike the movement of falling. So in the elements of geometry the quality straightness and that of minimum length—duration or effort in traversing a line —are antecedent and consequent, or else concomitant qualities which are essentially different in their natures, but so intimately joined in all experience and in our conceptive powers, that they seem to be different aspects of one and the same nature. Yet the fully adequate and constructive definition of straight lines as a sort, of which only one can be drawn between two given points, does not imply that this is the shortest that can be drawn, or the one soonest and easiest traversed. This constructive definition joined to the meaning of the word inclosure gives what is often regarded as an axiom, the more complex proposition, that two straight lines cannot inclose a space. Starting with these and other constructive definitions, with the most general axioms of quantity, and with postulates of construction, and combining them into more and more complex relations of magnitudes in extension, we arrive at geometrical theorems in which the protasis states the least possible that is essential as the cause, or reason, and the apodosis, or conclusion, defines succinctly the consequent, or effect; theorems in which the connections of these two terms is far from obvious, but is nevertheless necessary, at least in the abstract, or on the supposition of precise, real definition and construction. Reason and consequent imply one the other, or the nature of a cause determines that of its effect, because one is analyzed into relations already determined from fundamental propositions, and these relations serve to define, or constitute the other. It is not true in general that the effect is like its cause, or has a nature determined by that of its cause, but it is true that like causes produce like effects. Parents may be said with tolerable correctness to be the causes of their offspring resembling them, and hence in this case causes produce effects like themselves; yet it is more correct to say that the offspring resemble their parents, because both are products, though successive ones, of similar real causes and processes, some of which in nowise resemble or transfer their natures to their effects. Some implements and agents of the useful arts likewise are used to make precisely similar implements and agents, as a blacksmith’s hammer to produce a similar hammer, or fire to kindle another one, or to reproduce the easily ignited substances with which fires are kindled; yet in these cases the agent that produces its like is not the whole of the cause of production. The blacksmith’s forge and anvil and his arm and sight are concauses or conditions of this reproduction: and the nature of these does not re-appear in the effect, unless, as we have said, there is added to the conception of the aggregate of conditions, namely, to the conception of the iron, forge, welding-hammer, arm and sight combined, also the fact that these will produce an effect resembling one of its conditions. So in organic reproduction, the plant produces seed similar not to itself but to the seed from which it grew, and the new seed grows into a similar plant: and in this alternation in which the immediate cause really produces effects unlike itself there are many subordinate conditions and processes the similarity of which in the parent and offspring makes them similar through successive effects of similar causes, which are not of the same nature as their effect. It is only because one condition or element of the cause (the one which resembles its effect) is singled out and, in accordance with the practical usage of common language, is called the cause, on account of its prominence or conspicuousness, that it is at all proper to speak of the parent organism as the cause of the production of its offspring. The existence of the parent organism is a condition sine qua non of the production of its offspring, but there are other conditions equally indispensable, the natures of which in themselves are in no wise reproduced in the effects.—[1873.]